[PATCH v4 1/6] media: uvcvideo: Refactor URB descriptors

From: Kieran Bingham
Date: Tue Mar 27 2018 - 12:46:19 EST


We currently store three separate arrays for each URB reference we hold.

Objectify the data needed to track URBs into a single uvc_urb structure,
allowing better object management and tracking of the URB.

All accesses to the data pointers through stream, are converted to use a
uvc_urb pointer for consistency.

Signed-off-by: Kieran Bingham <kieran.bingham@xxxxxxxxxxxxxxxx>
Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>

---
v2:
- Re-describe URB context structure
- Re-name uvc_urb->{urb_buffer,urb_dma}{buffer,dma}

v3:
- No change

v4:
- Rebase on top of linux-media/master (v4.16-rc4, metadata additions)

drivers/media/usb/uvc/uvc_video.c | 49 +++++++++++++++++++-------------
drivers/media/usb/uvc/uvcvideo.h | 18 ++++++++++--
2 files changed, 45 insertions(+), 22 deletions(-)

diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
index aa0082fe5833..93048fbf4e82 100644
--- a/drivers/media/usb/uvc/uvc_video.c
+++ b/drivers/media/usb/uvc/uvc_video.c
@@ -1456,14 +1456,16 @@ static void uvc_free_urb_buffers(struct uvc_streaming *stream)
unsigned int i;

for (i = 0; i < UVC_URBS; ++i) {
- if (stream->urb_buffer[i]) {
+ struct uvc_urb *uvc_urb = &stream->uvc_urb[i];
+
+ if (uvc_urb->buffer) {
#ifndef CONFIG_DMA_NONCOHERENT
usb_free_coherent(stream->dev->udev, stream->urb_size,
- stream->urb_buffer[i], stream->urb_dma[i]);
+ uvc_urb->buffer, uvc_urb->dma);
#else
- kfree(stream->urb_buffer[i]);
+ kfree(uvc_urb->buffer);
#endif
- stream->urb_buffer[i] = NULL;
+ uvc_urb->buffer = NULL;
}
}

@@ -1501,16 +1503,18 @@ static int uvc_alloc_urb_buffers(struct uvc_streaming *stream,
/* Retry allocations until one succeed. */
for (; npackets > 1; npackets /= 2) {
for (i = 0; i < UVC_URBS; ++i) {
+ struct uvc_urb *uvc_urb = &stream->uvc_urb[i];
+
stream->urb_size = psize * npackets;
#ifndef CONFIG_DMA_NONCOHERENT
- stream->urb_buffer[i] = usb_alloc_coherent(
+ uvc_urb->buffer = usb_alloc_coherent(
stream->dev->udev, stream->urb_size,
- gfp_flags | __GFP_NOWARN, &stream->urb_dma[i]);
+ gfp_flags | __GFP_NOWARN, &uvc_urb->dma);
#else
- stream->urb_buffer[i] =
+ uvc_urb->buffer =
kmalloc(stream->urb_size, gfp_flags | __GFP_NOWARN);
#endif
- if (!stream->urb_buffer[i]) {
+ if (!uvc_urb->buffer) {
uvc_free_urb_buffers(stream);
break;
}
@@ -1540,13 +1544,15 @@ static void uvc_uninit_video(struct uvc_streaming *stream, int free_buffers)
uvc_video_stats_stop(stream);

for (i = 0; i < UVC_URBS; ++i) {
- urb = stream->urb[i];
+ struct uvc_urb *uvc_urb = &stream->uvc_urb[i];
+
+ urb = uvc_urb->urb;
if (urb == NULL)
continue;

usb_kill_urb(urb);
usb_free_urb(urb);
- stream->urb[i] = NULL;
+ uvc_urb->urb = NULL;
}

if (free_buffers)
@@ -1601,6 +1607,8 @@ static int uvc_init_video_isoc(struct uvc_streaming *stream,
size = npackets * psize;

for (i = 0; i < UVC_URBS; ++i) {
+ struct uvc_urb *uvc_urb = &stream->uvc_urb[i];
+
urb = usb_alloc_urb(npackets, gfp_flags);
if (urb == NULL) {
uvc_uninit_video(stream, 1);
@@ -1613,12 +1621,12 @@ static int uvc_init_video_isoc(struct uvc_streaming *stream,
ep->desc.bEndpointAddress);
#ifndef CONFIG_DMA_NONCOHERENT
urb->transfer_flags = URB_ISO_ASAP | URB_NO_TRANSFER_DMA_MAP;
- urb->transfer_dma = stream->urb_dma[i];
+ urb->transfer_dma = uvc_urb->dma;
#else
urb->transfer_flags = URB_ISO_ASAP;
#endif
urb->interval = ep->desc.bInterval;
- urb->transfer_buffer = stream->urb_buffer[i];
+ urb->transfer_buffer = uvc_urb->buffer;
urb->complete = uvc_video_complete;
urb->number_of_packets = npackets;
urb->transfer_buffer_length = size;
@@ -1628,7 +1636,7 @@ static int uvc_init_video_isoc(struct uvc_streaming *stream,
urb->iso_frame_desc[j].length = psize;
}

- stream->urb[i] = urb;
+ uvc_urb->urb = urb;
}

return 0;
@@ -1667,21 +1675,22 @@ static int uvc_init_video_bulk(struct uvc_streaming *stream,
size = 0;

for (i = 0; i < UVC_URBS; ++i) {
+ struct uvc_urb *uvc_urb = &stream->uvc_urb[i];
+
urb = usb_alloc_urb(0, gfp_flags);
if (urb == NULL) {
uvc_uninit_video(stream, 1);
return -ENOMEM;
}

- usb_fill_bulk_urb(urb, stream->dev->udev, pipe,
- stream->urb_buffer[i], size, uvc_video_complete,
- stream);
+ usb_fill_bulk_urb(urb, stream->dev->udev, pipe, uvc_urb->buffer,
+ size, uvc_video_complete, stream);
#ifndef CONFIG_DMA_NONCOHERENT
urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP;
- urb->transfer_dma = stream->urb_dma[i];
+ urb->transfer_dma = uvc_urb->dma;
#endif

- stream->urb[i] = urb;
+ uvc_urb->urb = urb;
}

return 0;
@@ -1772,7 +1781,9 @@ static int uvc_init_video(struct uvc_streaming *stream, gfp_t gfp_flags)

/* Submit the URBs. */
for (i = 0; i < UVC_URBS; ++i) {
- ret = usb_submit_urb(stream->urb[i], gfp_flags);
+ struct uvc_urb *uvc_urb = &stream->uvc_urb[i];
+
+ ret = usb_submit_urb(uvc_urb->urb, gfp_flags);
if (ret < 0) {
uvc_printk(KERN_ERR, "Failed to submit URB %u "
"(%d).\n", i, ret);
diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
index be5cf179228b..e056e5609068 100644
--- a/drivers/media/usb/uvc/uvcvideo.h
+++ b/drivers/media/usb/uvc/uvcvideo.h
@@ -481,6 +481,20 @@ struct uvc_stats_stream {

#define UVC_METATADA_BUF_SIZE 1024

+/**
+ * struct uvc_urb - URB context management structure
+ *
+ * @urb: the URB described by this context structure
+ * @buffer: memory storage for the URB
+ * @dma: DMA coherent addressing for the urb_buffer
+ */
+struct uvc_urb {
+ struct urb *urb;
+
+ char *buffer;
+ dma_addr_t dma;
+};
+
struct uvc_streaming {
struct list_head list;
struct uvc_device *dev;
@@ -529,9 +543,7 @@ struct uvc_streaming {
u32 max_payload_size;
} bulk;

- struct urb *urb[UVC_URBS];
- char *urb_buffer[UVC_URBS];
- dma_addr_t urb_dma[UVC_URBS];
+ struct uvc_urb uvc_urb[UVC_URBS];
unsigned int urb_size;

u32 sequence;
--
git-series 0.9.1